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3 Bananas Long: A Genetics Song

15 Feb

Enjoy this genetics song written for our young Willa.

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The big. ass. egg.

15 Nov

Womanhood is powerful. If ever you seek a concrete image to illustrate this, look at a human egg flanked by sperm.

The first thing you will notice is that the egg is huge. Sperm cells swarm like tiny rockets around a super planet. Continue reading

Genetic math: Is Ben Stiller his parents? Or his own damn self?

15 Nov
Ben Stiller

Ben Stiller. Creative Commons photo by Jerry Avenaim

How much of me is me?  Am I “destined” to become my mom?  Why do I “see myself” in my dad’s parents’ photographs, circa 1951, and not my mom’s?

There’s a saying that applies to all of us:

“Mirror, mirror, on the wall, I am my mother after all.”

But mirror, mirror, to be true, I’m half my mom and half dad, too.

And nature adds to her Great Tree a teensy dash of Only Me.

As we now discuss the proportional contributions of our genetic forebears, note that we are setting aside the countless, profoundly significant things that make us who we are that have nothing to do with cellular biology.  And, to be honest, we are even setting aside many aspects of cellular biology that make up our humanness but are not orchestrated by genes.  People are more than genetic casseroles.

Nonetheless we are endlessly and justifiably curious about the ingredients of the casseroles that are our genetic selves. And so for a brief, educational minute, let us contemplate the essence of Ben Stiller. Continue reading

Watch these chromosomes move!

21 Oct

Mitosis allows all living things to grow and reproduce. The genetic material inside of a parent cell is duplicated so that it can then be distributed equally into two daughter cells.

This spectacular video showing mitosis in action inside of a newt’s lung cell was created by E.D. Salmon and Vicki Skeen at the Salmon Lab, University of North Carolina at Chapel Hill. The video is used with permission. See more of their videos at http://www.bio.unc.edu/faculty/salmon/lab/salmonlabmovies.html.

The genetic alphabet

20 Oct

Illustration by D. Leja, courtesy of the National Human Genome Research Institute, http://www.genome.gov.

The genes in our chromosomes are often compared to recipes inside of a cookbook.

But if we were to open one of these cookbooks, we would find that the recipes are all written in a unique language.

Whereas we have 26 letters in our alphabet, the DNA alphabet is only four letters long: A, T, G, C.

Each letter represents a chemical base: adenine (A), thymine (T), guanine (G), and cytosine (C).

Looking at DNA directly, we see the As, Ts, Gs, and Cs arranged on that most famous genetic shape, the double helix.

To picture this shape, imagine you are holding a toy rubber ladder that you twist on both ends.  The sides of the ladder are sugar and phosphate molecules; the rungs of the ladder are As paired with Ts, or Cs paired with Gs, fitted together in units called base pairs.

If you unravel the DNA, you reveal the recipes of As, Ts, Cs, and Gs that are written into genes in the form of three-letter words called codons (so named because they are little codes). Continue reading

What keeps Woody Allen alive? Mitosis.

12 Oct

Woody Allen is alive.  Woody Allen is made out of cells.  And as long as he’s around to anguish over what life is all about, mitosis will keep Woody Allen ticking.

Mitosis in detail

Photo by Flickr user Electrolux Appliances.

Mitosis is the basic way in which everything in life gets duplicated and refreshed.

It’s the process by which a cell replicates its DNA and divides it into two equal parts.  This allows one “mother” cell to split into two “daughter” cells.

Right now in Woody Allen’s hair, for example, there are mother cells– think of them as Jewish mother cells if you like– and they’re sitting around saying, “Agh. I’m getting old. I’m getting tired.  I’m about to die.  How do I get this stuff out of my house and out to my kids?” Continue reading

In your grandmother’s womb: The egg that made you.

29 Sep

The cell you came from was once inside of your mother’s fetus in her mother’s womb.

Although I was born in 1976, the egg that I came from was created in my grandmother’s womb– somewhere in Georgia, in 1946.

Want to calculate the vintage of the egg you came from?  Take your mother’s date of birth and subtract about 20 weeks.

That’s true because unlike males, who constantly generate sperm after they hit puberty, girls are born with their one and only lifetime supply of eggs.  Around the 20th week of gestation, a female fetus has developed a reproductive system, including 6 to 7 million eggs in her ovaries.

The matrilineal line looks much like a nested Russian doll.

The egg that created you was formed inside of your mother’s fetus while she was inside of your grandmother’s womb.

UPDATE: A few comments have pointed to a recent study in mice that suggests the possibility that a woman’s supply of eggs might be replenished. Questions remain about this controversial finding that scientists are working to understand, verify and replicate. We think it’s premature to revise the textbooks, but it’s exciting to consider new possibilities in science and to follow how they are validated or refuted by the scientific process. This finding, if true, could have implications for fertility treatment, so we’ll stay tuned!

Where did Lady Gaga come from?

29 Sep

Photo by Creative Commons user The Cranky Geek, http://www.flickr.com/photos/jolissa/

Lady Gaga comes from New York. She has grandparents in West Virginia. Her ancestors came from Italy.

But the story we want to tell (with apologies, Gaga fans, for the bait and switch) is how Lady Gaga and the rest of us were at one time just one single cell.

That is the big “aha” moment in genetics: The realization that our parents have each given us half of themselves, and it comes together in a kind of a miraculous moment when the small rocket of a sperm penetrates the atmosphere of the giant planet that is the egg.      

The genomes combine and they begin to work together to multiply and to become, well, an inexplicable grassroots system of communication and sharing that builds something so large and complex and highly functional that in the end it forms a human being with huge capability and imagination that can make glam videos and outrageous contributions to fashion over decades and decades.
  

Imagine that a little cell can dream itself into Lady Gaga.  How that happens and stays with us is, for us, the real story about where we come from. 

This is the cool story of being embodied. 

Whether or not you relate this to divinity there’s an awesomeness to the fact that we start as single cells and grow into something that’s 10 to 20 trillion cells big.  That includes some 220 cell types that differentiate into eye cells and liver cells and hair cells…  All of that from a single cell: That’s a pretty neat trick. And that is part of the epic story that we will be telling during the life of this blog.